The Barracuda Spam Firewall 400 represents the right way to build an appliance-based e-mail firewall. It was the only unit in this review that was truly plug-and-play and was up and running with a live mail stream in less than five minutes.

When you first power up the Barracuda 400 you can use a console interface to configure the initial IP address. It's a simple process of telling the device what IP address it should use'probably the one where your mail comes into the network.

You can also tell it where to forward the mail (your mail server) after it has flowed into the appliance for cleaning.

Once you've completed the setup and rebooted, you can use the Web interface to manage the device. We found that at this point the Barracuda was working fine, so the Web interface came in handy for its graphical reports of the spam and viruses it was eliminating from your mail stream.

We also used the interface to force the appliance to download the latest firmware.

This causes the system to reboot, but the software never alerts you to this nor does it tell you it will sever your Internet connection.

Admins can perform a lot of basic maintenance through the Web interface.

You can tweak your spam scoring engines or change your quarantine policy. There is 50GB of storage space on the device if you want to keep suspected mail for a long time. During our testing, the device processed over 400,000 pieces of mail and never filled up past about 4 percent of capacity.

That said, we would have liked a few higher-end features in the management software, such as the ability to automatically bounce certain e-mail to a subset of users. But for most administration tasks, managing the Barracuda 400 is as easy as the initial setup.

When we dropped the device into our Spirent testbed of 300 simulated users, it held its own against viruses and spam.

It blocked 992 of 1,000 spam e-mails we sent it, one of the best marks in the review. Virus prevention was near-perfect: It stopped 999 of the 1,000 we sent it.

Moreover, the Barracuda 400 wasn't fooled into many false positives, allowing virtually all the legitimate e-mail through and quarantining only one real message as suspected spam.

At only $3,999, the Barracuda 400 is one of the most economical appliances in this review. If you're looking for an inexpensive way to get good protection for your mail stream without hassles, it's a great choice.